The present invention relates to a method of discriminating a bill or bank note as to whether the bill is placed with its obverse side directed upwardly or downwardly and whether the bill is damaged or not, as well as the kind of the bill.
A known system for discriminating a bill has n sensors (n being 1 or an integer greater than 1) disposed across the path of travel of the bill, and n channels for transmitting output signals from the sensors. In operation, several optimum channels which provide the most effective information corresponding to the operation mode and kind of bill are selected, and a bill pattern is obtained in accordance with the output signals from the optimum channels. Then, a comparison is made between the bill pattern thus obtained and reference patterns which are previously set up in accordance with the operation modes and the kind of the bill to discriminate the bill. For instance, in the case where a 10,000 bill is discriminated in the bill kind discrimination mode, one, two or more optimum channels which most distinctively provide the features of this bill are selected, and then a bill pattern is obtained in accordance with the output signals from these channels. This bill pattern is then compared with preset reference patterns to discriminate the bill.
In the conventional bill discriminating system, it is necessary to prepare a multiplicity of bill discriminating units having different reference patterns and adapted to be connected to different channels, corresponding to conbinations of the respective operational modes and the respective kinds of bills. Therefore, it is necessary to replace or change-over these bill judging units. Consequently, the bill discriminating system is expensive and uneconomical to maintain.